Stimulus discrimination is about being able to differentiate between the original stimulus and other different but related stimuli. It’s contrary to the concept of stimulus generalization, in which a subject is unable to discern an original stimulus from a host of other similar stimuli.
Let’s start with an example. A kid who patiently waits for their father every evening may start dancing on hearing the doorbell sound. They may start getting excited every time the doorbell rings. It’s referred to as stimulus generalization. However, they may be disappointed to discover that other family members also ring the same doorbell. It’s only after repeated disappointments that they recognize the particular pattern of the doorbell call made by their father. After that, they may not dance at every doorbell, but only if it rings a certain way. That’s when their father comes in. This is because now the child has developed stimulus discrimination.
Stimulus Discrimination after a Traumatic Event
People who have gone through a traumatic event suffer from the lack of stimulus discrimination. Similar events or stimuli may cause them to undergo the same feeling as caused by the previous traumatic event. Trauma survivors have a great tendency to mix, confound, and generalize different but related stimuli.
Survivors of trauma often experience an involuntary recollection of their past traumatic memories. They also show many involuntary avoidance responses, even in the absence of the real threat. It’s hypothesized that temporary stimuli associated with trauma can trigger an involuntary recall of traumatic memories. Specific triggers associated with trauma can generalize over time, changing from specific prompts to a broad range of associated, related, or similar stimuli. This is what we call stimulus generalization.
This generalization creates a broad range of stimuli that can cause feelings of distress. As a result, trauma survivors progressively become prone to avoid broader ranges of stimuli. Developing stimulus discrimination can be helpful for trauma survivors, making them react less to unrelated events. Stimulus generalization, on the other hand, can make a person confused or defensive.
While stimulus discrimination also manifests in operant conditioning, it’s more related to classical conditioning.